I am using the Rails helper datetime_select in one of my forms. I currently have a requirement to change the dropdowns for day, year,
Why not roll your own, just name the input fields in the same exact way that the date picker helper does, and you get all the back-end benefits while rolling a custom front-end. Or use the :order to have your date picker give the month selection, and use some javascript magic for the other input.
You can use a jquery datepicker and populate hidden fields with the same naming convention as the rails datepicker.